There has been proposed a developing device of a laser printer in which a toner cartridge is detachably attached to a developing case of the apparatus.
JP-A-7-225514 discloses a developing device in which a toner cartridge is detachably attached to a case of the developing device. Locking guide grooves are formed in the case of the developing device. In the toner cartridge, levers are swingably disposed on a support shaft which is laterally projected from right and left side walls of the toner cartridge, and which rotates a rotary vane. Engaging projections are disposed on level base plates through which the shaft is passed. In JP-A-7-225514, the toner cartridge is attached to the case of the developing device, and the levers are swung about the support shaft to cause the engaging projections to be fitted into the locking guide grooves, whereby the levers and the toner cartridge cannot be disengaged from the case of the developing device. Accordingly, a state of attaching the toner cartridge to the case of the developing device is maintained.
In the developing device disclosed in JP-A-7-225514, positions of fittings between the engaging projections of the toner cartridge and the locking guide grooves of the case of the developing device are located on the right and left sides of the toner cartridge. However, such positions of fittings between the engaging projections of the toner cartridge and the locking guide grooves of the case of the developing device are not located on the downstream side in the direction along which the toner cartridge is detached from the developing case. That is, a member which restricts a relative movement of the toner cartridge attached to the case of the developing device with respect to the case of the developing device is not disposed on the downstream side of the toner cartridge in the detaching direction.
Therefore, when a force of moving the toner cartridge in the detaching direction is applied to the toner cartridge, the toner cartridge may be maintained and may be detached from the case of the developing device.